In 1697, safely hidden in a bazaar booth, Henry Maundrell observed
the departure of the annual caravan from Ottoman Damascus to Mecca:

"After
these Horses came the Mahmal. This is a very large Pavilion of
black Silk, pitch'd upon the back of a very great Camel, and spreading
its Curtains all round about the Beast down to the ground. The
Pavillion is adorn'd at top with a Gold Ball, and with Gold Fringes
round about. The Camel that carries it wants not also his Ornaments
of large Ropes of Beads, Fish-shells, Fox-tails, and other such
fantastical finery hang'd upon his Head, Neck and Legs. All this
is design'd for the State of the Alcoran, which is placed with
great reverence under the Pavillion, where it rides in State both
to and from Mecca. The Alcoran is accompanied with a rich new
Carpet which the Grand Seigneur [Ottoman ruler] sends every year
for the covering of Mahomet's Tomb, having the old one brought
back in return for it, which is esteem'd of an inestimable value,
after having been so long next Neighbor to the Prophet's rotten
bones." (1)

Maundrell commented that the camel like the carpet was subsequently
accorded special treatment, never again having to work. This, and
the precise use of the carpet in Mecca are hearsay, but not the
kingly practice of a "carpet" gift to a sacred place.
What is interesting is the obvious public knowledge and religious
purpose of the gift, for royal custom could either have led or reinforced
general practice.